1990 plymouth laser runs rich then floods out



changed mass air flow sensor,water temperature sensor,oxygen sensor,fuel pressure regulator, new spark plugs


If you’re certain it’s running that rich and rich enough to flood out then check the fuel pressure regulator.
Pull the vacuum hose loose and check to see if there is gas in the hose.

A clogged catalytic converter can also cause the same symptoms.


OOps! You missed a component: the idle air control valve, and the air filter. Have you ever heard of Haynes? No, not the underwear people!
Let Haynes instruct you.


Keep throwing parts at it, and you’ll find the bad component soon enough. Or, get a multimeter and a noid light, and start doing a proper diagnosis by testing stuff. My first thoughts are to check the fuel pressure, not just replace the regulator, and use a stethoscope to listen to the injectors. I’d listen for the injector that is not ticking. Hint, the poor man’s stethoscope is a long screw driver and cupping your ear to the handle. Been using it for years.


One thing that can cause this is an open wire going from the PCM to the CTS so check the continuity of that wire. Also, check the resistance of the CTS to make sure it is still in calibration and moving as the engine warms up (even new parts may be bad).

Hope this helps.